McDonel, Patrick E. Program in Molecular Medicine, University of Massachusetts Medical School, Worcester, Massachusetts.
Last reviewed:August 2018
- Xist expression and localization
- Xist domains and associated proteins
- Mechanisms of Xist spreading and silencing of transcription on the Xi
- Links to Primary Literature
- Additional Readings
A long noncoding ribonucleic acid, specific to the female inactive X chromosome, that orchestrates X-chromosome inactivation in eutherian mammals. The X-inactive specific transcript, Xist (Fig. 1), is essential for inactivation of the X chromosome in female eutherian mammals (note that Eutheria is a higher-level taxon that includes all mammals, except monotremes and marsupials). In eutherian mammals, such as humans, rodents, and livestock, sex determination is controlled by the X and Y chromosomes. Females have two X chromosomes and males have an X and a Y, whereas both males and females have two copies of all other chromosomes (termed autosomes). In all somatic (non-germline) cells, however, the expression levels of most X-linked genes are the same among males and females, despite females having an extra X chromosome. This equalization, called dosage compensation, is essential for embryonic survival because it maintains the correct gene expression balance between sex chromosomes and autosomes in every somatic cell. See also: Cell (biology); Cell biology; Chromosome; Dosage compensation of the active X chromosome; Embryology; Eutheria; Gene; Genetics; Human genetics; Long noncoding RNAs (long ncRNAs); Mammalia; Ribonucleic acid (RNA); Sex chromosomes; Sex determination
The content above is only an excerpt.
for your institution. Subscribe
To learn more about subscribing to AccessScience, or to request a no-risk trial of this award-winning scientific reference for your institution, fill in your information and a member of our Sales Team will contact you as soon as possible.
to your librarian. Recommend
Let your librarian know about the award-winning gateway to the most trustworthy and accurate scientific information.
AccessScience provides the most accurate and trustworthy scientific information available.
Recognized as an award-winning gateway to scientific knowledge, AccessScience is an amazing online resource that contains high-quality reference material written specifically for students. Its dedicated editorial team is led by Sagan Award winner John Rennie. Contributors include more than 9000 highly qualified scientists and 42 Nobel Prize winners.
MORE THAN 8500 articles and Research Reviews covering all major scientific disciplines and encompassing the McGraw-Hill Encyclopedia of Science & Technology and McGraw-Hill Yearbook of Science & Technology
115,000-PLUS definitions from the McGraw-Hill Dictionary of Scientific and Technical Terms
3000 biographies of notable scientific figures
MORE THAN 17,000 downloadable images and animations illustrating key topics
ENGAGING VIDEOS highlighting the life and work of award-winning scientists
SUGGESTIONS FOR FURTHER STUDY and additional readings to guide students to deeper understanding and research
LINKS TO CITABLE LITERATURE help students expand their knowledge using primary sources of information